diff --git a/.github/workflows/master.yml b/.github/workflows/master.yml
index d893f761b5..0611e3bb87 100644
--- a/.github/workflows/master.yml
+++ b/.github/workflows/master.yml
@@ -11,14 +11,14 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        gradle-argument: [ 'assemble && ./gradlew check -x test','testWithJava11', 'testWithJava17', 'test -x testWithJava11 -x testWithJava17' ]
+        gradle-argument: [ 'assemble && ./gradlew check -x test','testWithJava11', 'testWithJava17','testWithJava21', 'test -x testWithJava11 -x testWithJava17 -x testWithJava21' ]
     steps:
       - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
       - name: build and test
         run: ./gradlew ${{matrix.gradle-argument}} --info --stacktrace
@@ -30,15 +30,16 @@ jobs:
             **/build/test-results/test/TEST-*.xml
             **/build/test-results/testWithJava11/TEST-*.xml
             **/build/test-results/testWithJava17/TEST-*.xml
+            **/build/test-results/testWithJava21/TEST-*.xml
   javadoc:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
       - name: Verify Javadoc
         run: ./gradlew javadoc --info --stacktrace
@@ -55,10 +56,10 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
       - name: publishToMavenCentral
         run: ./gradlew assemble && ./gradlew check -x test -x testng --info && ./gradlew publishToSonatype closeAndReleaseSonatypeStagingRepository -x check --info --stacktrace
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index f57a62ef75..07099c34a0 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -20,14 +20,14 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        gradle-argument: [ 'assemble && ./gradlew check -x test','testWithJava11', 'testWithJava17', 'test -x testWithJava11 -x testWithJava17' ]
+        gradle-argument: [ 'assemble && ./gradlew check -x test','testWithJava11', 'testWithJava17','testWithJava21', 'test -x testWithJava11 -x testWithJava17 -x testWithJava21' ]
     steps:
       - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
       - name: build and test
         run: ./gradlew ${{matrix.gradle-argument}} --info --stacktrace
@@ -39,15 +39,16 @@ jobs:
             **/build/test-results/test/TEST-*.xml
             **/build/test-results/testWithJava11/TEST-*.xml
             **/build/test-results/testWithJava17/TEST-*.xml
+            **/build/test-results/testWithJava21/TEST-*.xml
   javadoc:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
       - name: Verify Javadoc
         run: ./gradlew javadoc --info --stacktrace
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 8eb18b440b..4e1d5fb29f 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -21,10 +21,10 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - uses: gradle/actions/wrapper-validation@v5
-      - name: Set up JDK 21
+      - name: Set up JDK 25
         uses: actions/setup-java@v5
         with:
-          java-version: '21'
+          java-version: '25'
           distribution: 'corretto'
       - name: build test and publish
         run: ./gradlew assemble && ./gradlew check --info && ./gradlew publishToSonatype closeAndReleaseSonatypeStagingRepository -x check --info --stacktrace
diff --git a/AGENTS.md b/AGENTS.md
index 50afcbce83..369e771d62 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -7,5 +7,5 @@ This file provides context for AI assistants working with this codebase.
 When running tests, exclude the Java version-specific test tasks to avoid failures:
 
 ```bash
-./gradlew test -x testWithJava17 -x testWithJava11 -x testng
+./gradlew test -x testWithJava21 -x testWithJava17 -x testWithJava11 -x testng
 ```
diff --git a/build.gradle b/build.gradle
index a9276fe452..fd9a2d0979 100644
--- a/build.gradle
+++ b/build.gradle
@@ -357,6 +357,12 @@ tasks.withType(Test) {
     }
 }
 
+tasks.register('testWithJava21', Test) {
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
+}
+
 tasks.register('testWithJava17', Test) {
     javaLauncher = javaToolchains.launcherFor {
         languageVersion = JavaLanguageVersion.of(17)
@@ -385,6 +391,7 @@ tasks.register('testWithJava11', Test) {
 
 }
 
+test.dependsOn testWithJava21
 test.dependsOn testWithJava17
 test.dependsOn testWithJava11